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The estimates start from a construction cost of 2,850 reais per square meter, a value above the basic CUB because it already seeks to reflect a more complete scenario. The numbers do not include land, projects, and furniture, and vary according to each city and each standard.
Building a rental building is no longer a project restricted to large plots, and the cost varies greatly depending on the size of the construction. According to the architecture office of Jane Willhelm, architect (CAU/RS A99943-1), who works remotely for clients throughout Brazil, gathered three real projects to illustrate how much it costs to erect buildings with small units, ranging from a plot of just 36 square meters to a five-story building with twenty mini apartments. The examples show how scale directly influences the final cost per unit.
To standardize the comparison, all calculations start from an estimated construction cost of 2,850 reais per square meter, a reference adopted by the office itself for the first semester of 2026. It is worth a warning right from the start, that is, this value is an estimate of construction and is above the basic CUB precisely because it tries to cover more items. Even so, it does not include the land, the projects, the furniture, the fees, and the water and energy connections, costs that need to be included separately in the planning of any rental building.
Understanding the calculation basis before the numbers
The Basic Unit Cost is the official index of civil construction in Brazil, calculated monthly by the state construction industry unions, the Sinduscon, and provided for in Federal Law 4,591 of 1964.
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In 2026, the CUB for medium residential standard, known as R8-N, ranges from 2,100 to 2,500 reais per square meter in most states, according to union data.
In São Paulo, for example, Sinduscon-SP recorded 2,129.86 reais per square meter in January 2026.
The difference exists because the basic CUB covers only part of the construction and leaves out several relevant expenses.
According to the unions themselves and the Brazilian Chamber of Construction Industry, CBIC, the index does not include land, projects, special foundations, elevators, air conditioning, taxes, and the margin known as BDI.
Therefore, by adopting 2,850 reais per square meter, the office tries to reach an estimate closer to the actual construction expenditure, even though each land and each city impose variations that only a local budget can specify.
The small building on a 36 square meter plot
The first project impresses with the boldness of fitting on a plot of only 4 meters wide by 9 meters long, totaling 36 square meters.
In this space, the office developed a building with three completely independent units.
On the ground floor, there is a store of just over 24 square meters, with a pantry and bathroom, suitable for various types of commerce.
On the second floor, there is a studio apartment of almost 24 square meters, with an integrated kitchen, full bathroom, and laundry area under the stairs.
The two upper floors house the largest unit of the set, a loft with a double-height ceiling and 44 square meters.
In total, the building has 108 square meters of constructed area.
Applying the cost of 2,850 reais per square meter, the construction is estimated at approximately 309 to 310 thousand reais.
The appeal of the project lies in delivering three distinct sources of income on a minimal plot, catering to commerce, those seeking a studio, and those preferring a larger space.
The medium building with eight units and parking space
The second project occupies a flat mid-block plot, 10 meters wide by 20 meters long.
As the local city hall required parking spaces, the ground floor was designated for the garage, with two more floors of apartments above.
There are eight units in total, divided into two types, one of about 25 square meters and another of approximately 23 square meters, both with equipped kitchen, laundry area, bedroom, and bathroom.
The total constructed area reaches 270 square meters, of which about 195 are private area and the rest corresponds to condominium spaces.
The estimated construction cost is around 770 thousand reais, resulting in an average of approximately 96 thousand reais per unit.
According to the office, a design decision made a difference in this case, namely, positioning the staircase in the center of the lot instead of the front, which allowed for larger units and better space utilization.
The large building with twenty mini apartments
The third project is on another level, on a plot of land 12 meters wide by 37 meters long.
The building has five floors and comprises twenty mini apartments, distributed in two typologies, one of about 24 square meters and another of 29 square meters.
The units follow the same logic of a complete kitchen right at the entrance, living room, bedroom, and bathroom, with the larger version offering a bit more space between the rooms.
This project reveals the most significant data of the article, as the estimated cost per unit drops to about 70 to 71 thousand reais.
The explanation lies in the scale, as items like foundation, structure, roof, installations, and stairs are spread over a larger number of apartments.
In other words, the more units the land accommodates, the lower the proportional cost of each one tends to be, a factor that favors those investing in larger rental buildings.
Summary of the estimates of the three projects
- Small building: land of 36 m² (4 m x 9 m), 108 m² built, 3 properties (store, studio apartment, and loft). Estimated construction cost around 309 to 310 thousand reais.
- Medium building: land of 200 m² (10 m x 20 m), 270 m² built, 8 units plus garage. Estimated construction cost around 770 thousand reais, about 96 thousand reais per unit.
- Large building: land of 12 m x 37 m, 5 floors, 20 mini apartments. Estimated cost of about 70 to 71 thousand reais per unit.
- Calculation base: 2,850 reais per square meter, construction cost above the basic CUB, excluding land, projects, furniture, fees, and connections.
What these numbers don’t tell
As these are estimates, it’s important to emphasize the limits of these values to avoid surprises in the budget.
The costs presented refer only to the construction calculated by the built area and do not include the purchase of the land, which is usually one of the largest expenses, nor the architectural and engineering projects, the furniture shown in the images, the licenses, the taxes, and the definitive water and energy connections.
In real constructions, these items can significantly increase the total investment.
Another point is that each plot of land is subject to specific municipal legislation, which changes what can be built.
The office itself points out that identical projects on plots of the same size can yield more or fewer units, depending on local rules regarding setbacks, height, and land use.
Therefore, any national estimate serves as an initial reference, and the definitive budget for a rental building only comes from a project adapted to the land and city, with a local technical manager.
The three projects show that building a rental building is feasible on different scales, but the cost per unit strongly depends on the size of the development.
From the small 36-square-meter building to the twenty-apartment building, it is clear that the dilution of fixed costs favors larger projects, while smaller ones compensate through the diversity of income sources.
In all cases, however, the construction estimate is just the starting point of an account that needs to include many other expenses.
And you, have you ever thought about turning a plot of land into a source of income with a rental building? Comment on which of the three models makes more sense for your reality, whether you prefer fewer larger units or many compact units, and what questions you still have about the costs of building to rent in Brazil. The conversation is open for both beginner and experienced investors to exchange ideas.
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